In Book 4, Section 91 of the Masnavi, Rumi explores the epistemological concept that each human sense is restricted to its own specific domain of perception. He illustrates this using the analogy of master craftsmen, where a master of one trade is entirely ignorant of the work of another. Rumi argues that a sense's inability to perceive phenomena outside its domain—just as hearing cannot perceive visual forms—does not negate the existence of those phenomena. This epistemological framework highlights the limitations of empirical perception and prepares the ground for accepting higher, non-sensory or spiritual realities that lie beyond ordinary apprehension.